1. Field of the Invention
The present invention relates to a setting tool, in particular, to an expandable gas-driven setting tool for driving fastening elements, such as bolts, nails and the like in a constructional component and including a housing, a bolt guide axially displaceably arranged in the housing, a magazine for the fastening elements projecting sidewise from the bolt guide and displaceable in a direction opposite the setting direction against a biasing force of a first spring relative to the bolt guide, a second spring located between the housing and the magazine and having a maximal biasing force acting in the setting direction and an excursion greater than a maximal biasing force and an excursion of the first spring, and a piston guide axially displaceably arranged in the housing.
2. Description of the Prior Art
European Publication EP-0 743 141 B1 discloses an explosive powder charge-operated setting tool having a housing and an axially displaceable bolt guide arranged in the housing and projecting beyond the housing in a setting direction. A magazine for fastening elements is suspended sidewise from the bolt guide. The magazine is displaced relative to the bolt guide in a direction opposite the setting direction against a spring-biasing force. The magazine provides for storing of a plurality of fastening elements, such as bolts or nails, which are located in guide sleeves connected with each other in a belt-like manner, and for advancing of the fastening elements into the bolt guide. The fastening elements are displaced in a direction toward the bolt guide with a spring-biased slide located in the magazine. On the magazine, there is provided a pin that is supported against the magazine with a spring and is pressed toward the tool housing when the setting tool is pressed against a constructional component. The bolt guide is so displaced that the displacement of the fastening elements is blocked. The maximal biasing force applied to the pin and the corresponding spring excursion of the spring are greater than the spring-biasing force and excursion of a spring located between the bolt guide and magazine. This is necessary to insure the forward movement of the fastening elements located in the magazine.
For actuating the setting tool, the housing should be displaced relative to the bolt guide over a certain so-called xe2x80x9cpress-on path.xe2x80x9d To this end, in a first stage of the press-on displacement, a setting direction-side, press-on surface of the bolt guide is set against a constructional component, and the housing is pressed in the setting direction. During the press-on step, the magazine is displaced in the setting direction relative the bolt guide until the magazine abuts the constructional component. The spring, which is arranged between the housing and the magazine, reaches during the first press-on phase or stage, the setting direction-side, end surface of the housing and displaces the magazine, because of its greater biasing force and excursion, relative to the bolt guide in the setting direction until the magazine contacts the constructional component. At the same time, the spring, which is located between the bolt guide and the magazine, becomes preloaded. In this position of the magazine, the advancement of the fastening elements from the magazine into the bold guide is prevented. After the setting process, when the setting tool is lifted off the constructional component, first, the magazine, the bolt guide, and the piston guide are displaced together relative to the housing. Only, when the magazine and the bolt guide have been displaced relative to the housing so far that the spring or the pin does not contact the housing anymore, the displacement of the magazine relative to the bolt guide takes place under the biasing force of the spring arranged between the bolt guide and the magazine, until the magazine reaches its initial position. In this way, the lifting off the displacement blocking means takes place with a time delay.
The drawback of the known setting tool consists in that the pin, which is not arranged coaxially with the press-on direction, applies a torque to the displacement parts, in particular to the magazine. This leads to an asymmetrical load and, as a result, to jamming of the movable parts.
Accordingly, an object of the present invention is to so modify a setting tool of the type discussed above that a reliable forward displacement of the fastening elements is insured, and the above-noted drawbacks are eliminated.
This and other objects of the present invention, which will become apparent hereinafter, are achieved by providing, on the magazine, at least one engaging surface that at least partially surrounds the bolt guide, and by providing an annular element circumferentially surrounding the piston guide and located in a receiving space formed in the housing for transmitting a biasing force of the spring which is located between the magazine and the housing to the at least one engagement surface of the magazine upon the setting tool being pressed against the constructional component.
The annular element is arranged coaxially with the press-on or setting direction.
These novel features of the present invention permits to pivot the magazine with the bolt guide by 360xc2x0 as its cooperation with the annular element and, thereby, a forward advancement is possible in any pivotal position. Further, the application of force to the movable parts during the press-on stage takes place symmetrically, which prevents jamming of the movable parts, and no decrease of the press-on force because of jamming takes place.
The annular element, which is guided in the front, setting direction-side, of the housing, is biased in the setting direction by a compression spring likewise coaxially arranged with respect to the setting direction. The compression spring is supported against the housing or a sleeve fixedly secured in the housing.
Advantageously, the receiving space is formed as a socket in which both the annular element and compression spring are arranged. A stop in the housing can prevent the annular element from falling out of the housing. These measures permit to provide a compact and easy to assemble setting tool.